Vai? Why Not? I'm not surprised if Paul Gilbert will play "Fly Me to the Moon". Apart from being a soloist, when these wizards are tasked to play for a song from whoever artist they would always fit and PLAY FOR THE SONG. Not overdo it and make another super guitarish kind of tune. If in case you didn't notice, his rhythm playing is amazing. The guitar is always a part of the rhythm section, it can be very effective as an accompaniment.